An overview of the necessary thymic contributions to tolerance in transplantation

- Thymic biology, T cell maturation, and thymic involution are reviewed.
- Central and peripheral transplantation tolerance mechanisms, are discussed in detail.
- We present the latest evidence highlighting the thymus's role in tolerance induction.
- Experimental methods of thymic manipulation as a path to human tolerance are discussed.

The thymus is important for the development of the immune system. However, aging leads to predictable involution of the thymus and immunodeficiency. These immunodeficiencies may be rectified with thymic rejuvenation. Atrophy of the thymus is governed by a complex interplay of molecular, cytokine and hormonal factors. Herein we review the interaction of these factors across age and how they may be targeted for thymic rejuvenation. We further discuss the growing pre-clinical evidence defining the necessary and sufficient contributions of the thymus to successful tolerance induction in transplantation.